/*
 *  SableJBDD, a Java Binary Decision Diagram package.
 *  Copyright (C) 2003  Feng Qian
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
//$Id: EmptyBddCache.java,v 1.1 2004/03/12 00:15:37 fqian Exp $

package SableJBDD.bdd.internal;

import SableJBDD.bdd.JBddNode;
import SableJBDD.cache.CacheProfiler;
import java.io.PrintStream;

/**
 * An abstract cache uses three integers as the key.
 *
 * @author Feng Qian
 */
public class EmptyBddCache extends CacheProfiler implements BddCache{
  public EmptyBddCache() {}

  /**
   * Looks up a bdd node by f, g, and h.
   * Returns null if no such node exists.
   */
  public final JBddNode lookup(Unique f, Unique g, Unique h){
    return null;
  }

  /**
   * Puts the ite(f,g,h) in the cache.
   */
  public final void put(Unique f, Unique g, Unique h, JBddNode result) {}
  
  public void reset() {}

  public int size() {return 0;}
}
